Spatio-temporal filter and method

Abstract

A system, apparatus and methods are disclosed for the spatial and temporal processing of time dependant array data using analog signal processors. In one embodiment, a programmable array of switched capacitors is used to provide tunable parameters for controlling the desired processing of input data streams. The switched capacitor implementation of a spatial filter provides a massively parallel device that can be programmed to perform isotropic and spatially-oriented anisotropic filtering with low power demands. The system further includes the ability to combine differently filtered output streams with independent multiplicative weights. In another embodiment, the nonlinear spatio-temporal motion energy of a two-dimensional image stream data is computed. The spatial-temporal filter is able to combine multiple analog filters, both spatial and temporal, to perform complex spatial-temporal filtering operations implemented by Gaussian kernel filtering chips. It enables the use of analog spatial-temporal filtered data provided by the chip for computing scene motion energy.

1. A programmable apparatus operable for spatial frequency filtering of two dimensional (2-D) signal data comprising a planar array of grounded capacitors charged in proportion to signal data values, wherein each grounded capacitor of said planar array of grounded capacitors is interconnected to other grounded capacitors by at least one switched capacitor to provide electrical connection therebetween and allow charge sharing between said planar array of said grounded capacitors through said intervening switched capacitors for the purpose of performing 2-D spatial domain filtering; and wherein each of said grounded capacitors comprising said planar array has an (x,y) coordinate and neighboring grounded capacitors disposed at (x,y) offset coordinates of (0,+1), (+1,0), (0,−1) and (−1,0) with respect to said (x,y) coordinates of each said grounded capacitor for effecting isotropic or oriented anisotropic spatial filtering; and a clock providing clock pulses operable for switching said switched capacitors for adjusting the spatial extent of the spatial frequency filtering. 
   
   
     2. The apparatus of  claim 1  wherein each grounded capacitor is further electrically connected by a switched capacitor to neighboring grounded capacitors at (x,y) coordinate offsets including but not limited to (+1, +2), (+2, +1), (+2, −1), (+1, −2), (−1, −2), (−2, +1), (−2, +1), and (−1, +2) with respect to (x,y) coordinates of said each grounded capacitor. 
   
   
     3. The apparatus of  claim 1  wherein each grounded capacitor is further electrically connected by a switched capacitor to neighboring grounded capacitors at (x,y) coordinate offsets including but not limited to (+1, +1), (+1, −1), (−1, −1), and (−1, +1) with respect to (x,y) coordinates of said each grounded capacitor. 
   
   
     4. The apparatus of  claim 1  further comprising a reference capacitor operable for differencing filtered signal data from said signal data. 
   
   
     5. The apparatus of  claim 4  wherein said one and two dimensional signal data comprises a data array having at least one row of signal data and wherein said clock provides independent switched capacitor control of a row of signal data for implementing independent one-dimensional spatial filters for performing computations including, but not limited to wavelet scalogram computations. 
   
   
     6. The apparatus of  claim 1  further comprising means for changing operability of said apparatus from a low pass spatial frequency filter to a high pass spatial frequency filter.